It has long been known that prescribed exercises are valuable to rehabilitate injured and surgically reconstructed muscles, tendons and other tissues and to improve cardiovascular performance. A variety of mechanical devices have been developed and used by therapists to supplement the exercises. The health and fitness-conscious have also developed devices to improve muscle tone, body shape and athletic performance and some of these devices have also been employed in rehabilitation programs after injury and/or surgery. Often the goal of the various devices has been to increase the enjoyment level of the exercise in the hope that the length of the exercise period would be increased.
Early devices were often designed to enable the user to move forward by simulating a jumping motion. Cashoty teaches a device designed for use by children whereby the user stands on a platform supported by legs attached to support posts by leaf springs. The user holds the upper portions of the support posts and jumps up and down on the platform ultimately advancing forward as he jumps. (U.S. Pat. No. 1,617,665) A similar device in the form of a stilt on wheels is taught by Schauweker in U.S. Pat. No. 2,096,310. The platform of this device is for one foot, so two stilts must be mounted at the same time. Hoffmeister, in U.S. Pat. No. 3,110,492, developed jumping stilts that did not move on wheels but left the ground as the user jumped up and down. Gaberson discloses the pogo stick-like exerciser where there are two footrests affixed to a single pole that is spring activated to propel the user up and down as the pole moves forward. (U.S. Pat. No. 3,116,061) Adams, et al. teaches a stationary pogo stick for children in U.S. Pat. No. 3,915,451. A bouncing motion was achieved by literaly sitting on a bouncing ball held in a framework with handle bars in the device of Perez Blanco. (U.S. Pat. No. 5,009,415)
More recently exercise devices began to imitate the same motion as climbing a flight of stairs. These exercisers were developed to provide enhanced aerobic benefits as well as build muscle mass and strength. In all of these exercisers, the handlebars or other support system are external to the platform or steps and are stationary while the user moves up and down. Such devices utilized hydraulic cylinders (U.S. Pat. No. 5,071,115 to Welch); elastomeric torsion springs (U.S. Pat. No.5,129,873 to Hendersen et al.); and a sprocket and chain used to turn a drum with tension adjustable by cord and bias springs (U.S. Pat. No. 5,242,340 to Jerome).
McFee, in U.S. Pat. No. 4,645,197, designed a board exerciser that can be adjusted according to the weight of the user who stands on a platform and holds movable handles. The platform is made to oscillate by flexing the knees and exerting pressure on a handle. Elastic springs or compressed coil springs are employed.
None of aforementioned devices provide support to the user such that a post-surgical patient, an older person or one with infirmities can safely and beneficially utilize them. There is a need for an exercise device that is completely adjustable to the requirements of the user, that safely supports the user, and that provides exercise and rehabilitative benefits atttained from motions ranging from merely flexing the knees to full jumping capabilities.